Apparatus for applying a liquid or viscid coating medium onto a moving fiber material web

ABSTRACT

An apparatus applies a liquid or viscid coating medium onto a moving material web, especially one made of paper or cardboard. A coating mechanism first applies the coating medium onto an applicator element or an applicator roll, which subsequently transfers the coating medium at a coating location onto the material web in the form of a coating layer. Furthermore, if so desired, a doctoring device can be positioned at a doctor station, adjacent to the coating location, on the downstream side relative to the movement of the material web for the purpose of smoothing and/or metering the coating. The coating apparatus incorporates an apparatus for the generation and/or supplying of a fluid, preferably steam. This apparatus is positioned adjacent to the coating location or to the doctor station on the downstream side relative to the movement L of the material web.

This is a divisional of application Ser. No. 09/229,090 filed Jan. 8,1999, now U.S. Pat. No. 6,171,653.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for applying a liquid orviscid coating medium onto a moving material web, especially one made ofpaper or cardboard.

2. Description of the Related Art

An exemplification of a known apparatus for applying a liquid or viscidcoating medium onto a moving material web is illustrated in FIG. 2a. Thecoating apparatus includes an applicator roll 12 and a counter roll 14.The two rolls, 12 and 14, form a nip through which material web 16 runsin the direction of feed. Applicator roll 12 is coated with a liquid orviscid coating medium by use of a coating mechanism 18. This medium issubsequently transferred onto the material web 16 in the area of thecoating location S. Applicator roll 12 and counter roll 14 are driven inopposite directions around their respective axes A and B as indicated byarrows P and P′. Such coating apparatuses are applied, for example, infilm coating processes, roll coating processes and size presses.

Coating apparatus 10 usually experiences problems in the area Sp—locatedadjacent to the coating location S, on the downstream side relative tothe movement of the material web 16—as the material web 16 separatesfrom the outer surface 12 a of roll 12. The pre-metered coating ofcoating medium 20 being applied onto the outer surface 12 a is onlypartially transferred in the nip onto the material web 16. A part 20 bof the coating medium 20 adheres to the outer surface of roll 12, andtherefore, returns back to the coating mechanism 18. Those experiencedin the art, refer to this effect as “film splitting”.

In the process of film splitting, “coating medium threads” F (FIG. 2b)develop between the coating medium 20 being applied onto the materialweb 16 and the remaining layer 20 b of coating medium on roll 12—similarto the honey threads that are formed between a spoon that is pulled froma honey jar. When these threads F are torn, it is possible to developdroplets or particles 20 c of the coating medium 20, which is reflectedin the formation of spray mist N. Accordingly, it can be said that thespray mist is formed by the particles and droplets 20 c of the coatingmedium 20, which, for example, are torn from the previously appliedcoating 20 a by the adhesive force of applicator roll 12.

Due to the aforementioned formation of the spray mist, the quality ofthe coated material web can be compromised in several ways. For example,small craters can form on the outer surface of the coated material web.Furthermore, the remaining parts of the torn-off coating medium threadsF can cause a so-called “orange skin effect”. Additionally, there-deposit of droplets or particles 20 c in an area removed from thespray area Sp can lead to an irregular structure of the material web'scoating surface. The spray mist also causes other drawbacks such as acontamination of the coating apparatus.

The risk of encountering the above-stated disadvantages increases as thefeed speed of the material web 16 increases, as the area specificcoating weight on the material web 16 increases, and as the absorbencycapability and/or the bibulousness of the material web 16 decreases. Toavoid the aforementioned disadvantages of the state of the art, it wassuggested in a summary report issued by the “Tappi Metered Size PressForum” by Dr. Hans W. Maurer (weekly publication for paper manufacturing17, 1997, page 827) to vary the composition of the coating medium. Thisapproach, however, has proven to be impractical.

SUMMARY OF THE INVENTION

The present invention provides a coating apparatus of the type mentionedabove, which eliminates the spray mist from the coating medium, or, at aminimum, reduces its adverse effects on the coating result, so that auniform coating can be achieved.

A coating mechanism first applies the medium onto an applicator elementor an applicator roll, which subsequently transfers the coating mediumat a coating location onto the material web in the form of a coatinglayer, or it is entered into a coating sump, formed between the materialweb and a limiting element or limiting roll in which the coating mediumis deposited onto the material web. If so desired, a doctoring devicecan be positioned at a doctor station, adjacent to the coating location,on the downstream side relative to the movement of the material web, forthe purpose of smoothing and/or metering the coating.

This problem is solved by providing an apparatus to generate and/orsupply fluid, preferably steam. The apparatus is positioned adjacent tothe coating location or doctor station on the downstream side relativeto the movement of the material web.

For the sake of simplicity, further elaboration of this invention willbe conducted by using steam as the fluid that is being introduced in thearea of the coating location. It is, however, understood that otherfluids can also be successfully used, not only in the area of thecoating location, but also in the area of a doctor station at which thecoating is smoothed and/or metered by use of a roll doctor, which alsohas the tendency to develop spray mist.

In accordance to this invention, a device provided to surround the sprayarea Sp, located adjacent to coating location S on the downstream siderelative to the movement L of the material web, with a steam-saturatedatmosphere, preferably steam produced from water. This causes, on onehand, a reduction in the surface tension of the coating medium, whichtends to favorably affect the thread and droplet formation. On the otherhand, the steam-saturated atmosphere causes a slowing of the dryingprocess of the coating medium, as well as the medium droplets that arebeing applied onto the material web, so that the structures on thecoating that are being produced by tearing threads and droplets canbleed into the coating without leaving any marks. This results in a moreuniform coating.

It has been proven to be advantageous to use steam that no longerabsorbs any water, i.e., saturated and superheated steam.

Regardless of whether the steam is produced near the coating apparatusor whether the steam is produced in a remote area relative to thecoating apparatus and subsequently piped to the spray area, it isdesirable for the steam-generating apparatus and/or the steam supplyapparatus to point the steam directionally towards the coating location.

For example, the steam-generating apparatus and/or the steam supplyapparatus can include a steam supply line in the area of the coatingapparatus. The line has at least one steam discharge opening facing thecoating location.

In accordance to a first design variation, the aforementioned advantagesprovided by this invention can be realized with a steam-saturatedatmosphere which is, by and large, stationary in the spray area, if oneignores the effects of the material web movement, the steam supplyeffects and any residual spray mist effects.

According to an alternative design variation, it is, however, alsopossible to obtain these same advantages with a dynamic steam-saturatedatmosphere, which is achieved by blowing the steam into the spray area,past the steam-generating apparatus and/or the steam supply apparatus,and then exiting past the spray area. For that purpose, the steamdischarge opening that forms the wall sections of the steam supply line,or the wall sections downstream of the steam discharge opening, can beformed nozzle-like, preferably with the smaller nozzle area on thedownstream side.

The movement of the steam that is discharged can be affected byappropriate shaping of the outer surfaces of the steam-generatingapparatus and/or the steam supply apparatus in such a way that a furthersmoothing of the coating on the material web can be achieved. Forexample, the steam-generating apparatus and/or the steam supplyapparatus can be designed as a flow restrictor unit in such a way thatthe steam-saturated atmosphere, which is being discharged in the areaadjacent to the coating location, is done so at a fluid velocity thatforces at least part of the droplets having formed in the approximatearea of the coating location back into the coating. Since the droplets,as well as the coating, are still sufficiently moist in the describedarea as a result of the steam-saturated atmosphere, the droplets, whichare forced back, bleed into the coating without leaving any marks.

In order to guard against any contamination of the coating apparatus asa result of any residual spray mist remaining in the area in spite ofthe steam-generating apparatus and/or the steam supply apparatus(designed as described herein, a collection device is positioned on theside of the steam-generating apparatus and/or the steam supply apparatusthat is facing away from the coating location. This device collectsthose coating medium droplets and particles which have not been returnedto the material web, and/or collects those coating medium droplets andparticles that are not adhering to the coating.

Although the droplets of the residual spray mist do not dry as quicklybecause of the steam-saturated atmosphere, it is appropriate to guardagainst a “baking” of the coating medium on the splash panel of thecollection device. To this end, it is suggested to design a splash panelthat includes cooling fins and/or a cooling coil and/or a heatexchanger. Additionally, or alternatively, this splash panel can beequipped with a device to supply a rinsing agent. The collected coatingmedium and/or the rinsing agent can be removed from the collectiondevice via a discharge line. It is further possible to position asuction apparatus at the side of the steam-generating apparatus and/orthe steam supply apparatus that is facing away from the coating locationin order to evacuate the steam-saturated atmosphere and/or those coatingmedium droplets and particles which have not been returned to thematerial web, and/or to collect those coating medium droplets andparticles that are not adhering to the coating. In doing so, the suctionapparatus and the aforementioned collection device should be designed asone functional unit.

The steam-generating apparatus and/or the steam supply apparatusdescribed in this application can be applied to an apparatus designedfor a one-sided application of the coating medium onto the material web,or it can be applied to an apparatus designed for a two-sidedapplication. In the case of the two-sided application of the coatingmedium onto the material web, each side of the material web is equippedwith a steam-generating apparatus and/or the steam supply apparatus.

In order to combat the adverse effects of film splitting on especiallysusceptible sections of the material web with a more intense steamtreatment, a plurality of steam-generating and/or steam supply sectionsare positioned in a sequential manner and perpendicular to the materialweb. These units are capable of being controlled independently from oneanother, at least in terms of the amount of steam per unit time that isbeing discharged.

This invention further relates to a process for the application of aliquid or viscid coating medium onto a moving material web, especiallyone made of paper or cardboard. With respect to the advantages that canbe achieved with this coating process, the aforementioned discussion ofthe coating apparatus applies.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of this invention,and the manner of attaining them, will become more apparent and theinvention will be better understood by reference to the followingdescription of embodiments of the invention taken in conjunction withthe accompanying drawings, wherein:

FIG. 1a is a side, schematic view of a coating apparatus of the presentinvention, for the purpose of applying a coating onto a material web;whereby, two embodiments of the steam-generating apparatus and/or thesteam supply apparatus are shown on either side of the material web;

FIG. 1b is a side, schematic view of another embodiment of thesteam-generating apparatus and/or supply apparatus shown on the leftside of FIG. 1a;

FIG. 2a is a side, schematic view of a coating apparatus, according tothe state of the art;

FIG. 2b is an enlarged view of coating location S of FIG. 2a;

FIG. 3 is an approximate schematic, side view of another embodiment of acoating apparatus of the present invention including a collectiondevice;

FIG. 4 is an approximate schematic, side view of another embodiment ofan apparatus designed to coat a material web on both sides of a materialweb, including collection devices positioned on either side of thematerial web; and

FIG. 5 is an approximate schematic, side view of yet another embodimentof a coating apparatus of the present invention including a suctionapparatus.

Corresponding reference characters indicate corresponding partsthroughout the several views. The exemplifications set out hereinillustrate one preferred embodiment of the invention, in one form, andsuch exemplifications are not to be construed as limiting the scope ofthe invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings and particularly to FIG. 1, there is acoating apparatus, designed in accordance to this invention, which islabeled with 110. The coating apparatus 110 facilitates the indirectapplication of liquid or viscid coating medium 120 and 120′ onto amaterial web 116 moving in the direction as indicated by the arrow L.The coating apparatus 110 includes two applicator rolls 112 and 112′which are in contact with the material web 116 in the area of thecoating location S, as well as with the coating mechanisms 118, 118′,whose purpose is to apply the coating medium 120 and 120′ onto the outersurfaces 112 a, 112 a′ of the applicator rolls 112, 112′. The applicatorrolls revolve around their respective axes A, A′ in opposite rotationaldirection relative to one another, as indicated by arrows P and P′,resulting in the coating medium 120 and 120′ being transferred onto theouter surface 112 a, 112 a′ of each roll 112, 112′ for subsequenttransfer to coating location S. The layers of coating medium beingdeposited onto material web 116 are labeled with 120 and 120′ in FIG.1a. The remaining coating layer (the result of the film splittingeffect) deposited on the outer surfaces 112 a and 112 a′ of theapplicator rolls 112, 112′ are labeled in FIG. 1a as 120 b and 120 b ′.

A steam-generating apparatus and/or the steam supply apparatus 122 and122′ is provided on each side of the material web 116, and is positionedin the spray or splash area, adjacent to coating location S, on thedownstream side relative to the movement L of the material web 116.

The steam-generating apparatus and/or the steam supply apparatus 122shown on the right side of FIG. 1a includes a steam supply line 124positioned directionally perpendicular Q to the material web 116. Thisline includes a plurality of openings 124 a—facing the sprayarea—through which steam D, supplied through line 124, can exit withoutdirectional guidance, as indicated by the three small arrows in FIG. 1a.With this design, the quantity of steam provided via the steam supplyline 124 to the spray area Sp is equivalent to the amount of steam thatsubsequently escapes from the spray area Sp due to the movement of thematerial web 116, the rotation of the applicator roll 112, and othereffects.

In contrast to the design described above, the steam-generatingapparatus and/or the steam supply apparatus shown on the left side ofFIG. 1a uses excess steam, provided via the steam supply line 124′ andexpelled into the spray through a nozzle-shaped steam exit slot 124 b′,so that a flow of steam exits the spray area Sp, as indicated in FIG. 1aby the two arrows on each side of the slot-type nozzle 124 b′, even whenthe material web 116 and applicator roll 112′ are stationary.Furthermore, the outer surface of the steam supply line 124′ andslot-type nozzle 124 b′ are shaped in a way that forces spray mistdroplets that might develop between the stated outer surfaces and thematerial web 116 right back to the coating layer 120 a′.

In the design according to FIG. 1a, the walls of the supply line 124′and the slot-type nozzle 124 b′ are a one-piece design. According to thealternative shown in FIG. 1b, a steam-generating apparatus and/or thesteam supply apparatus 222′ includes a slot-type nozzle body 224 b′,fitted on steam supply pipe 224′, which is provided with steam dischargeopenings 224 a′. Nozzle body 224 b′ is glued, soldered, welded orotherwise fastened to the pipe 224′ in a leak proof manner. This lastmentioned method of attachment allows a lateral movement and a turningof the nozzle, as well as an adjustment of the gap width of the nozzle.

In order to avoid any residual spray mist N that might develop todeposit on coating layer 120 a′, a collection device 126 is positionedadjacent to coating location S on the downstream side relative to themovement L of the material web, behind the steam-generating apparatusand/or the steam supply apparatus 122′. Collection device 126 includes asplash panel 128 whose end that is facing the material web 116 is alsopointing in the opposite direction with respect to the feed directionand is positioned in a way that allows a gap of approximately 5 mm to 50mm, preferably 30 mm, between the material web 16 and the edge of thesplash panel 128. At the lower part of the collection device 126 thereis a collector 130, or more precisely, a collector duct in which thecoating medium that drains off of the splash panel 128 collects prior toit being discharged via drain line 132 into either a waste container forsubsequent disposal, or into a coating medium reservoir for later use.In order to enhance the discharge effectiveness, it is possible toconnect a source of sub-atmospheric pressure source 135 to drain line132, which, if sized appropriately, can also function as a suctionapparatus for the purpose of eliminating any residual spray mist. Withthe aid of a separator (not shown), the individual (spray) components,which are drawn from the collection device 126, can be separated fromone another and re-used.

Since the coating medium 120′ has a temperature of typically in therange of 30 to 60 degrees C., there is a danger that collection device126 also warms up during operation, resulting in a condition that allowsthe coating medium 120′ to dry on splash panel 128, causing a build-upof coating residue which is commonly referred to as “baking”. This layerof residue must be removed from time to time. In order to facilitate asubstantially maintenance-free operation of the collection device,cooling fins 134 are attached to the outside of splash panel 128, theside facing away from the coating location S. These cooling fins 134result in an improvement in heat transfer between the collection device126 and the surrounding air. As a result of this cooling effect, thedrying of the coating medium 120 after its deposit onto the splash panel128 is sufficiently delayed so that the coating medium runs off thesplash panel 128 without leaving any significant residue. In addition, arinsing agent, preferably water, can be supplied through line 136 ontosplash panel 128 to rinse off coating medium 120 into collector duct130.

Collection device 126 can be made simply and cost-effectively, forexample, as a sheet metal construction.

Although the above-described invention is elaborated by using steam asthe fluid of choice, it should, at this point, be clearly stated thatany kind of fluid can be used that has the capability to reduce thesurface tension of the coating medium. The fluid can guard against thequick drying of the coating medium or eliminate the formation of thecoating medium spray mist, or more precisely, guard against thedisadvantageous effects of the spray mist on the coating quality. It ispossible, for example, to use alcohol as a fluid. Additionally, theeffect of the fluid on the formation of the spray mist can be furtherenhanced by choosing the appropriate proper temperature of the fluid.Depending on the type of fluid, optimum fluid temperatures could behigher or lower.

Several other design alternatives of the above-mentioned collectiondevice will be discussed in the section below:

The core idea of a simple, cost-effective collection device is thesplash panel. A splash panel is positioned with one of its ends adjacentto the material web and pointing in opposite direction relative to thefeed direction. This allows the momentum of the coating particles to bereduced as they impact the splash panel, thereby minimizing thepossibility of the droplets bouncing back from the splash panel. Inorder to increase the effectiveness of absorbing the particles, it isnaturally desirable to position the collection device as closely aspossible to the material web. However, there must be a minimum safetydistance maintained between the collection device and the material web,especially in light of the possibility of a fluttering material web, ora tear-related wind-up condition of the material web around a counterroll positioned in the area of the coating location. As a goodcompromise between these two opposing design considerations, it issuggested that the end of the splash panel facing the material web bepositioned at a distance of 5 mm to 10 mm from the material web.

In order to avoid the captured coating medium drying on the splash panelcausing a fouling condition, there are provisions for the splash panelto be equipped with cooling elements such as cooling fins, preferably onthe side of the splash panel facing away from the coating location. Inaddition to “passive” cooling fins, designs can also encompass “active”cooling elements, i.e., a cooling circuit through which cooling fluidflows. As a result of the cooling effect, the coating medium runs offthe splash panel without leaving any significant amount of residue,resulting in a collection device that can be operated substantiallymaintenance-free over an extended time period.

A well-designed collection device is equipped with a collector duct atthe bottom to collect the coating medium particles. Additionally, oralternatively, the collection device can also be equipped with adischarge system at its bottom for easy disposal of the collectedcoating medium. To enhance the drainage effectiveness, a source ofsub-atmospheric pressure can be connected to the discharge system.

A collection device positioned below the material web can—beyond theadvantageous effects of the uniformity of the coating—also contribute tothe cleanliness of the entire coating apparatus, since the coatingmedium that is being discharged at the bottom of the collection devicecan be captured.

In cases where the coating medium is applied onto both sides of thematerial web, especially when the material web runs vertically in thearea of the coating location, a collection device is positioned on eachside of the material web.

A design of the collection device which utilizes sheet metalconstruction proves to be especially cost-effective and simple tomanufacture. Fundamentally, the collection device can also be made ofsynthetic or other suitable materials.

Further, it is possible to position a suction apparatus adjacent to thecoating location, on the downstream side relative to the movement of thematerial web, in order to evacuate the coating medium droplets andparticles which have not been returned to the material web. Also, thosecoating medium droplets and particles that are not adhering to thecoating can be collected. The suction apparatus can include, forexample, a discharge line and an air suction ventilator positioned inthe discharge line, with the inlet opening to the discharge line beingadjacent to the material web. The airflow, generated by the air suctionventilator and directed towards the inlet opening, yields a highlyefficient method of collecting the coating particles of the spray mist

An especially high collection efficiency can be achieved if there is acollection device ahead of the suction apparatus as explained above.

FIG. 3 depicts a coating apparatus, which is labeled with 1110. Thecoating apparatus 1110 facilitates the indirect application of liquidand viscid coating medium 1120 onto a material web 1116 moving in thedirection as indicated by arrow L. The coating apparatus 1110 includesan applicator roll 1112, which is in contact with the material web 1116in the area of the coating location S, as well as with the coatingmechanism 1118, whose purpose is to apply the coating medium 1120 ontothe surface 1112 a of the applicator roll 1112. The applicator roll 1112revolves around its axis A, resulting in the coating medium 1120 beingtransported from the coating mechanism 1118 to the coating location S.

Material web 1116 is wrapped around counter roll 1114 in the area of thecoating location S. Counter roll 1114 runs in opposite rotationaldirection relative to roll 1112 as indicated by arrows P′. Rolls 1112and 1114 are driven in a manner so that their respective outer surfaces1112 a and 1114 a run relatively slip-free in the area of contact withthe material web 1116. The coating medium deposited onto the materialweb 1116 is labeled as F in FIG. 3.

Especially at high running speeds of the material web 1116, a spray mistN is likely to develop downstream of the coating location S, especiallyin the area where the material web 1116 lifts off the outer surface 1112a of roll 1112. The coating medium particles 1120 a that form spray mistN can either be liquid or viscid particles from the coating medium 1120,or can be particles that have already dried.

In order to avoid the coating medium particles 1120 a of the spray mistN being re-deposited onto the coating F, a collection device 1122 ispositioned adjacent to coating location S, on the downstream siderelative to the movement L of the material web. Collection device 1122includes a splash panel 1124 with one of its ends 1124 a being adjacentto the material web 1116 and the other end 1124 b being removed from thematerial web. Collection device 1122 also includes side panels 1126, ofwhich only one is shown in the approximate schematic of FIG. 3.Collection device 1122 is designed in the form of a sheet metalconstruction.

In the exemplification represented in FIG. 3, the splash panel 1124 isshaped and connected to side panels 1126 in a way that places thecollection device 1122 like an open box, with the opening in the area of1122 a pointing in the opposite direction relative to the feed directionL. The upper paneling of collection device 1122, which is formed by theupper end 1124 a of splash panel 1124, runs against the feed direction Ltowards the material web 1116 so that its outer-most edge 1124 a 1 ispositioned approximately 5 to 10 mm from the material web 1116. Thelower paneling of collection device 1122, which is formed by the lowerend 1124 b of splash panel 1124, as shown in the attachedexemplification, is shaped in form of a collector 1128 in which thecoating medium 1120 that runs off back panel 1124 c is collected priorto its discharge through drain line 1130, either into a waste containerfor later disposal or into a coating medium reservoir for future use. Asub-atmospheric pressure source 1131 can be attached to the drain line1130 to enhance the discharge-effectiveness.

Since the coating medium 1120 is typically at a temperature ofapproximately 50 degrees to 60 degrees C., there is the danger that thecollection device 1122 also heats up to this temperature level duringoperation of the coating apparatus 1110. In this case, the solventcontained in the coating medium 1120, i.e., water, would quicklyevaporate upon contacting the splash panel 1124 and, therefore, would“bake” the coating medium 1120 onto the splash panel 1124. A layer ofresidue would rapidly form on splash panel 1124, which must be removedfrom time to time. In order to facilitate a substantiallymaintenance-free operation of the collection device 1122, cooling fins1132 are attached to the outside of splash panel 1124, the side facingaway from the coating location S. These cooling fins 1132 result in animprovement in heat transfer between the collection device 1122 and thesurrounding air. As a result of the cooling effect brought about by thecooling fins 1132, the evaporation of the solvent in the coating medium1120 upon contact with the splash panel 1124 is sufficiently delayed sothat the coating medium runs off the splash panel 1124 and into thecollector 1128 without leaving any significant residue.

It should be noted here that the upper end 1124 a, the lower end 1124 band the back panel 1124 c of the splash panel 1124 can be designed asseparate box-type elements. It is also possible, that all components ofthe duct are designed as one monolithic piece. It should be furthernoted that the cooling fins 1132 attached to the collection device 1122can be substituted by cooling coils through which cooling fluidcirculates.

FIG. 4 illustrates a coating apparatus 1210, designed to apply coatingmedium 1220 on both sides of the material web 1216 moving in thedirection L. The coating apparatus 1210 includes two coating mechanisms1218 and 1218′. Additionally, there are two applicator rolls 1212 and1212′ which revolve around their respective axes A, A′ in oppositerotational direction relative to one another (indicated by arrows P andP′), resulting in the coating medium 1220 being transported from thecoating mechanisms 1218, 1218′ to the material web 1216. A spray mist Ndevelops on both sides of the material web 1216, adjacent to coatinglocations S and S′, on the downstream side relative to the movement L ofthe material web 1216. This spray mist N is captured by the collectiondevices 1222 and 1222′ for the purpose of avoiding its deposit on thelayers of coating F and F′ on the material web 1216, and, therefore,adversely affecting its quality. With respect to the construction of thecollection devices 1222 and 1222′, reference is made to the elaborationof the collection device 1122 shown in FIG. 3.

FIG. 5 shows an additional embodiment of a coating apparatus. Thecoating apparatus 1310 includes an applicator 1318, whose function is toapply the coating medium 1320 onto the outer surface 1312 a ofapplicator roll 1312. The applicator roll 1312 revolves around its axisA, as indicated by arrow P, resulting in the coating medium 1320 beingtransported from coating mechanism 1318 to coating location S, where itis deposited onto a moving material web 1316, moving in the direction asindicated by arrow L.

Material web 1316 is wrapped around counter roll 1314 in the area of thecoating location. Counter roll 1314 revolves around its axis B inopposite direction relative to applicator roll 1312, as indicated byarrow P′.

A spray mist N forms from coating material 1320 and develops adjacent tocoating location S on the downstream side relative to the movement L ofthe material web. In order to avoid the spray mist N depositing on thecoating layer of material web 1316, coating apparatus 1310 is equippedwith a suction apparatus 1340, as shown in FIG. 5. The suction apparatus1340 includes a discharge line 1342 whose opening 1342 a is adjacent toand faces coating location S. The suction line 1342 is equipped with aair suction ventilator 1344, which generates a suction in the area ofthe inlet opening 1342 a. This results in the coating medium particles1320 a of the spray mist N being evacuated, similar to the vacuumcleaner principle, so that none of these particles can reach the coatinglayer F.

As indicated in FIG. 5 by the dashed line, the inlet opening 1342 a canalso incorporate a collection device 1322, whose advantages have beenexplained above by the exemplification represented in FIG. 3. By usingan air suction ventilator 1344 which offers sufficient power, the sprayduct system 1322 could be eliminated.

While this invention has been described as having a preferred design,the present invention can be further modified within the spirit andscope of this disclosure. This application is therefore intended tocover any variations, uses, or adaptations of the invention using itsgeneral principles. Further, this application is intended to cover suchdepartures from the present disclosure as come within known or customarypractice in the art to which this invention pertains and which fallwithin the limits of the appended claims.

What is claimed is:
 1. An apparatus for applying a coating medium onto amoving fiber material web having a direction of movement, said apparatuscomprising: an applicator element configured for transferring a coatinglayer of the coating medium onto the fiber web at a coating location,said applicator element being configured for jointly defining a coatingsump with said fiber web immediately before said coating locationrelative to the direction of movement of the fiber web; a coatingmechanism associated with said applicator element, said coatingmechanism configured for applying the medium onto said applicator; asteam device configured for at least one of generating and supplyingsteam, said steam device being disposed adjacent to and after saidcoating location relative to the direction of movement of the fiber web;and a collection device disposed on a side of said steam devicesubstantially opposite said coating location, said collection devicebeing configured for collecting droplets and particles of the coatingmedium that adhere to neither of the fiber web and the layer of coatingmedium, said collection device including a splash shield having acooling device, said cooling device comprising at least one of aplurality of cooling fins, a plurality of cooling coils and a heatexchanger.
 2. The apparatus of claim 1, wherein said steam devicecomprises a steam supply line having at least one steam dischargeopening directed toward said coating location.
 3. The apparatus of claim2, wherein said steam supply line includes a plurality of wall sectionsdefining said steam discharge opening, said steam discharge openingcomprising a nozzle tapering in a direction of steam flow.
 4. Theapparatus of claim 2, wherein said steam supply line includes aplurality of wall sections disposed downstream from said steam dischargeopening relative to a direction of steam flow, said wall sectionscomprising a nozzle tapering in said direction of steam flow.
 5. Theapparatus of claim 1, wherein said steam device has a flow restrictingshape.
 6. The apparatus of claim 1, wherein said splash shield of saidcollection device includes a rinsing device configured for supplying arinsing agent.
 7. An apparatus for applying a coating medium onto amoving fiber material web having a direction of movement, said apparatuscomprising: an applicator element configured for transferring a coatinglayer of the coating medium onto the fiber web at a coating location,said applicator element being configured for jointly defining a coatingsump with said fiber web immediately before said coating locationrelative to the direction of movement of the fiber web; a coatingmechanism associated with said applicator element, said coatingmechanism configured for applying the medium onto said applicator; asteam device configured for at least one of generating and supplyingsteam, said steam device being disposed adjacent to and after of saidcoating location relative to the direction of movement of the fiber web;and a suction apparatus disposed on a side of said steam devicesubstantially opposite said coating location, said suction apparatusbeing configured for at least one of: evacuating at least one of afluid-saturated atmosphere and droplets and particles of the coatingmedium that do not adhere to the fiber web; and collecting said dropletsand said particles of the coating medium that do not adhere to the layerof coating medium.
 8. An apparatus for applying a coating medium onto amoving fiber material web having a direction of movement, said apparatuscomprising: an applicator element configured for transferring a coatinglayer of the coating medium onto the fiber web at a coating location,said applicator element being configured for jointly defining a coatingsump with said fiber web immediately before said coating locationrelative to the direction of movement of the fiber web; a coatingmechanism associated with said applicator element, said coatingmechanism configured for applying the medium onto said applicator; asteam device configured for at least one of generating and supplyingsteam, said steam device being disposed adjacent to and after saidcoating location relative to the direction of movement of the fiber web;and a second steam device associated with an opposite side the fiberweb, said apparatus being configured for applying the coating medium totwo sides of the fiber web.
 9. An apparatus for applying a coatingmedium onto a moving fiber material web having a direction of movement,said apparatus comprising: an applicator element configured fortransferring a coating layer of the coating medium onto the fiber web ata coating location, said applicator element being configured for jointlydefining a coating sump with said fiber web immediately before saidcoating location relative to the direction of movement of the fiber web;a coating mechanism associated with said applicator element, saidcoating mechanism configured for applying the medium onto saidapplicator; a steam device configured for at least one of generating andsupplying steam, said steam device being disposed adjacent to and aftersaid coating location relative to the direction of movement of the fiberweb; and at least a second steam device and a third steam device, saidsteam devices being substantially aligned in a direction substantiallyperpendicular to the fiber web, a rate of steam flow of each of saidsteam devices being independently controllable.